The II series introduced NuBus which would become the standard expansion bus for the entire Macintosh line for almost a decade. The Mac II models were the first to support color displays and display resolutions larger than the 512×342 of the compact Macintosh design.

The Mac II series were the first Macintosh models to use a m68k processor other than the Motorola 68000. Except for the original Mac II which launched the line with a 68020 clocked at 16 MHz, they exclusively used the Motorola 68030 microprocessor, even after the Motorola 68040 was introduced. Apple would eventually adopt the '040 with the introduction of the Quadra 700 and 900, positioning these models as high-end workstation-class machines for graphics and scientific computing, while continuing to release Mac II-series models as mainstream desktop computers.

During the Macintosh II series' lifespan, they rose to become among the most powerful personal computers available. The Macintosh II was later surpassed by the Macintosh Quadra series. The Macintosh LC and Performa lines continued the II's 68030 technology long after the 68040 was introduced and the PowerBook continued to use the '030 into the Power Macintosh era.